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Dive into the research topics where Nihat Uluocak is active.

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Featured researches published by Nihat Uluocak.


The Journal of Urology | 2011

Factors Affecting Complication Rates of Ureteroscopic Lithotripsy in Children: Results of Multi-Institutional Retrospective Analysis by Pediatric Stone Disease Study Group of Turkish Pediatric Urology Society

Hasan Serkan Dogan; Bulent Onal; Nihat Satar; Cem Aygun; Mesut Piskin; Orhan Tanriverdi; Serhat Gürocak; Levent Mert Gunay; Berk Burgu; Ender Ozden; Oktay Nazli; Erim Erdem; Selcuk Yucel; Aykut Kefi; Deniz Demirci; Nihat Uluocak; Ibrahim Atilla Aridogan; Tahsin Turunc; Veli Yalcin; Mehmet Kilinc; Kaya Horasanli; Mustafa Tan; Tarkan Soygür; Saban Sarikaya; Hakan Kilicarslan; Burak Turna; Hasan Erdal Doruk; Serdar Tekgül

PURPOSE We evaluated factors affecting complication rates of ureteroscopy for pediatric ureteral calculi. MATERIALS AND METHODS We retrospectively evaluated 642 children who underwent ureteroscopy at 16 Turkish centers between 2000 and 2010. Semirigid ureteroscopy was used with various calibers to treat 670 ureteral units in 660 sessions. Complications were evaluated according to the Satava and Clavien classification systems. Univariate and multivariate analyses were done to determine predictive factors affecting complication rates. RESULTS A total of 367 females and 265 males were studied. Mean±SD patient age was 90.2±51.4 months (range 4 to 204). Mean±SD stone size, operative time and postoperative hospital stay were 8.9±4.7 mm, 45.8±23.8 minutes and 1.8±2.8 days, respectively. At a mean±SD followup of 13.3±17.6 months 92.8% of patients were stone-free and efficacy quotient was 90.3%. Complications, which occurred in 8.4% of patients (54 of 642), were intraoperative in 25 (Satava grade I to II in 22), early postoperative in 25 (Clavien grade I to II in 23) and late postoperative in 4 (all grade III). While operative time, age, institutional experience, orifice dilation, stenting and stone burden were statistically significant on univariate analysis, multivariate analysis revealed that operative time was the only statistically significant parameter affecting the complication rate. CONCLUSIONS Semirigid ureteroscopy is effective, with a 90% stone-free rate and efficacy quotient. Most complications are low grade and self-limiting. Our results confirm that prolonged operative time is an independent predictor of complications, and should be considered when choosing and performing the treatment modality.


Urology | 2002

A prospective, randomized protocol to examine the efficacy of postinternal urethrotomy dilations for recurrent bulbomembranous urethral strictures.

Murat Tunc; Ahmet Tefekli; Ates Kadioglu; Tarik Esen; Nihat Uluocak; Necdet Aras

OBJECTIVES The high recurrence rate is still the major complication of endoscopic treatment of urethral stricture disease. To compare the outcome of patients who underwent direct vision internal urethrotomy (DVIU) and then followed a protocol that randomized them to either our urethral dilation protocol or consecutive DVIUs for the treatment of their urethral stricture. METHODS A total of 37 patients, who had undergone at least two DVIUs to treat their recurrent urethral strictures, were enrolled in this study. They were randomized into two groups. The etiology and location of the strictures were similar, and their length ranged from 0.5 to 2 cm in each group. In group 1 (n = 18), the patients were observed by regular visits and uroflowmetry profiles after the initial DVIU and consecutive DVIUs were considered when the stricture recurred. In group 2 (n = 19), patients received urethral dilations with Benique dilatators (maximal 21F) under intraurethral anesthesia, beginning 10 days after the initial internal urethrotomy, according to the following protocol: weekly for the first month, once after 3 and after 6 months, and then once each year. RESULTS After a median follow-up of 30 months, the urethral stricture recurred within 12 months in 55.6% (n = 10) of group 1, and consecutive DVIUs were indicated. During the same follow-up period, recurrence was observed in 2 patients (10.5%), 9 months and 2 years after randomization, in group 2 (P <0.05). The mean maximal urinary flow rate in groups 1 and 2 at last follow-up was 7.8 +/- 3.7 and 21.0 +/- 8.7 mL/s, respectively (P <0.01). CONCLUSIONS We suggest a regular, simple urethral dilation protocol for patients with recurrent bulbomembranous urethral stricture shorter than 2 cm, because this significantly allays the stricture recurrence rate, possibly eliminates the need for consecutive DVIU, and reduces morbidity.


International Braz J Urol | 2014

The effects of carvedilol on ischemia-reperfusion injury in the rat testis

Bekir Suha Parlaktas; Dogan Atilgan; Ali Akbas; Fatma Markoc; Fikret Erdemir; Huseyin Ozyurt; Nihat Uluocak

OBJECTIVE To analyze the oxidative damage and histopathological alterations caused by ischemia-reperfusion (I/R) injury and ameliorative effects of carvedilol (CVD) in the rat testis. MATERIALS AND METHODS Twenty-one male rats were randomized into 3 groups as follows: Group I (n = 7); control (sham) group, Group II (n = 7); I/R group, in which I/R injury was performed by torsing the left testis 720 ° clockwise for 2 hours and detorsing for 2 hours. Group III (n = 7); CVD treatment group; in addition to I/R process, one-dose of CVD was administered (2mg/kg, i.p) 30 min. before detorsion. Levels of antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) and levels of malondialdehyde (MDA) and protein carbonyl (PC) were determined in testicular tissues and serum of rats. Testicular tissues were also examined histopathologically and Johnsen scores were determined. RESULTS Activities of SOD and GSH-Px in serum and testicular tissues were increased by I/R, but administration of CVD decreased these levels (p < 0.001 and p = 0.001). Significantly increased MDA levels in serum and testicular tissues were decreased by CVD treatment (p < 0.001 and p = 0.001). Concerning PC levels in serum and testicular tissues, there was no statistically significant difference between the groups (p = 0.989 and p = 0.428). There was not a statistically significant difference in terms of mean Johnsen scores between the groups (p = 0.161). CONCLUSIONS Administration of CVD decreased oxidative damage biochemically in the rat testis caused by I/R injury, but histopathologically no change was observed betwe¬en all of the groups.


Asian Journal of Andrology | 2014

The biochemical effects of ischemia-reperfusion injury in the ipsilateral and contralateral testes of rats and the protective role of melatonin.

Bekir Suha Parlaktas; Dogan Atilgan; Huseyin Ozyurt; Ali Akbas; Fikret Erdemir; Nihat Uluocak

Testicular torsion (TT) is a serious urologic emergency that is observed in adolescent males and that can lead to infertility if left untreated. The ischemia-reperfusion (I/R) injury due to TT has been implicated in the pathogenesis of testicular damage. We investigated the effects of melatonin on oxidative damage in the ipsilateral and contralateral testes of rats induced by unilateral TT. A total of 21 prepubertal male Wistar albino rats were divided into three groups, each consisting of seven rats. In Group 1 (SHAM group): a sham operation to the left testis and bilateral orchiectomy were performed. In Group 2 (I/R group): I/R injury was created by rotating the left testis 720° in a clockwise direction for 2 h and detorsing the testis after 2 h. Group 3 (I/R + MEL group): rats were subjected to I/R injury and one-shot melatonin injection (50 mg kg−1, intraperitoneal (i.p.)). The testes of the rats were excised bilaterally in all groups. The testicular tissue activities of antioxidant catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase enzymes (GSH-Px), and the tissue levels of malondialdehyde (MDA), protein carbonyl (PC) and nitric oxide (NO) were determined. Administration of melatonin caused a significant decrease in lipid peroxidation and enzyme activities in the ipsilateral testis when compared with the control group (P < 0.05). All of the changes in the enzyme activities of the contralateral testis were insignificant (P > 0.05). MDA levels were significantly altered in the contralateral testis (P = 0.009). Melatonin administration decreased the deleterious effects of I/R injury in the ipsilateral torted testes of the rats. The contralateral testes were slightly affected by unilateral TT.


European Urology | 2001

Is Selective Internal Spermatic Venography Necessary in Detecting Recurrent Varicocele after Surgical Repair

Ahmet Tefekli; Selahittin Çayan; Nihat Uluocak; Arzu Poyanli; Turgut Alp; Ates Kadioglu

Objectives: Surgical varicocele repair can be complicated by postoperative recurrence. The aim of this study is to evaluate the diagnostic value of scrotal color Doppler ultrasonography (SCDU) and selective internal spermatic venography (SISV) in detecting recurrent venous reflux after conventional varicocelectomy. Materials and Methods: A total of 36 men (mean age 30.1 ± 4.3 years) with a persisting left unilateral varicocele and abnormal semen parameters more than 12 months after conventional varicocele repair were evaluated with physical examination, semen analyses, SCDU and SISV. Results: The median interval between primary varicocelectomy and presentation was 13 (range 12–16) months. Physical examination at that time revealed a grade– I left varicocele in 22 and a grade–II left varicocele in 14 patients. Semen analyses showed oligoasthenozoospermia in 30 patients (83%), asthenozoospermia in 4 (11%) and oligozoospermia in 2 (6%). Although all patients had reflux on SCDU, SISV confirmed reflux in 8 (22%) cases. SISV was not able to document recurrence in 28 cases (78%) that were detected by SCDU. Conclusions: Considering clinical findings, confirmed with SCDU, and semen parameters as the reference point in the diagnosis of recurrent varicocele, the sensitivity of SISV in the radiological documentation of recurrence was 22%. SISV was unable to document the recurrence in 78% of cases implying that reflux was not through internal spermatic veins. Thus, we conclude that SISV is neither necessary nor sufficient in the evaluation of recurrent varicocele.


Experimental and Therapeutic Medicine | 2014

Pomegranate (Punica granatum) juice reduces oxidative injury and improves sperm concentration in a rat model of testicular torsion-detorsion

Dogan Atilgan; Bekir Suha Parlaktas; Nihat Uluocak; Fikret Erdemir; Huseyin Ozyurt; Unal Erkorkmaz; Hüseyin Aslan

The present study aimed to evaluate the effect of pomegranate juice (PJ) on oxidative stress (OS) and sperm concentration in a rat model of testicular torsion-detorsion. A total of 21 Wistar albino rats were randomly divided into three groups, each consisting of seven rats, as follows: i) control group, which underwent sham surgery; ii) ischemia/reperfusion (I/R) group, designed to determine the effects of the testicular torsion-detorsion process on rats; and iii) PJ+I/R group, designed to evaluate the effect of PJ on the OS and sperm cell concentrations induced by the torsion-detorsion process. In the PJ+I/R group, the rats were given 0.4 ml/day PJ orally over a period of eight weeks prior to surgery. Ipsilateral orchiectomy was carried out and 5-cm3 blood samples were obtained from the inferior vena cava of all rats. Biochemical analyses were performed to calculate the superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels in the testicular tissue and serum. The concentrations of spermatids, spermatocytes and spermatogonia in the seminiferous tubules were assessed using histopathological methods. Serum and tissue SOD and MDA levels were significantly higher in rats from the I/R group compared with the control group (P<0.001). PJ treatment significantly decreased the SOD and MDA levels in both the serum and testicular tissue of the rats (P<0.001). The spermatid, spermatocyte and spermatogonia concentrations were significantly reduced in the I/R group compared with the control group (P<0.001). PJ treatment significantly improved the concentrations of spermatids, spermatocytes and spermatogonia compared with those in the I/R group (P=0.008). The experimentally established testicular torsion-detorsion model led to OS in the rat testes. Daily consumption of PJ prior to surgery reduced OS parameters and improved sperm cell concentrations.


International Journal of Urology | 2006

Comparison of the effects of on-pump versus off-pump coronary artery bypass surgery on serum prostate-specific antigen levels

Bekir Suha Parlaktas; Erdinc Naseri; Nihat Uluocak; Altay O Elalmis; Fikret Erdemir; Ilker Etikan

Aim:  To compare the effects of coronary artery bypass operation with or without extracorporeal circulation on serum total prostate‐specific antigen levels.


The Scientific World Journal | 2014

The Effects of Trimetazidine and Sildenafil on Bilateral Cavernosal Nerve Injury Induced Oxidative Damage and Cavernosal Fibrosis in Rats

Dogan Atilgan; Bekir Suha Parlaktas; Nihat Uluocak; Fikret Erdemir; Fatma Markoc; Oguzhan Saylan; Unal Erkorkmaz

Aim. The aim of this study was to compare the effects of sildenafil and trimetazidine on bilateral cavernosal nerve injury-induced oxidative damage and fibrotic changes in cavernosal tissue in rat model. Material and Methods. A total of 32 male Sprague-Dawley rats were randomly divided into 4 groups; each group consist 8 rats (control, BCI, BCI + TMZ, and BCI + sildenafil groups). Tissue superoxide dismutase (SOD), malondialdehyde (MDA), and protein carbonyl (PC) levels were determined biochemically and distribution of cavernosal fibrosis density among groups was performed histopathologically. Results. Tissue SOD levels in BCI group were significantly lower than the control group (P < 0.05). Tissue MDA and PC levels in BCI group were significantly higher than the control group (P < 0.05). TMZ and sildenafil administration significantly increased tissue SOD levels (P < 0.05) and reduced tissue MDA and PC levels (P < 0.05). Histologically, the degree of cavernosal fibrosis and collagen density was higher in BCI group in comparison to control, TMZ-treated, and sildenafil-treated groups. Conclusion. BCI caused oxidative damage and increased cavernosal fibrosis in rat penis. TMZ and sildenafil treatment decreased oxidative damage and reduced the degree of fibrosis in penile tissue due to BCI.


Urology | 2008

Positional changes in voiding dynamics of children with non-neurogenic bladder dysfunction.

Nihat Uluocak; Tayfun Oktar; Ömer Acar; Olga İncesu; Orhan Ziylan; Unal Erkorkmaz

OBJECTIVES To investigate the effect of certain positions on voiding dynamics in children with non-neurogenic bladder dysfunction. METHODS A total of 29 patients (10 male, 19 female) with non-neurogenic overactive bladder were enrolled. None of the patients had voiding phase dysfunction. Male patients were told to urinate in three positions (sitting, squatting, standing). Female patients did not void while standing. During voiding, maximum urinary flow rate (Qmax), detrusor pressure at maximal flow (Pdet-Qmax), and intra-abdominal pressure at maximal flow (Pabd-Qmax) were recorded. After voiding in one position, the bladder was re-distended. The same procedures were repeated for the three different positions. Then patients were told to perform three drinking-voiding cycles without the catheter in place. After recording Qmax, residual urine was measured with ultrasonography. The differences between these parameters were analyzed. RESULTS The mean (+/- standard deviation) patient age was 11.10 +/- 2.94 years (range, 6-16 years). In girls, the mean Pdet-Qmax value in the sitting and squatting positions was 43.11 +/- 16.74 cm H(2)O and 35.21 +/- 10.67 cm H(2)O, respectively (P = .028). Girls voided with a significantly higher Qmax in sitting and squatting positions than boys, regardless of the presence of a catheter. The mean Pdet-Qmax value in the squatting position was 59.20 +/- 20.45 cm H(2)O in boys and 35.21 +/- 10.67 cm H(2)O in girls. The presence of a catheter significantly lowered mean maximal urinary flow rates in sitting and squatting positions. CONCLUSIONS This is the first study to demonstrate the effect of voiding positions on pressure flow study results in children. Our results show that voiding dynamics are influenced by different voiding positions in children with non-neurogenic bladder dysfunction.


Urology Annals | 2012

Effects of melatonin on partial unilateral ureteral obstruction induced oxidative injury in rat kidney

Dogan Atilgan; Bekir Suha Parlaktas; Nihat Uluocak; Fikret Erdemir; Fatih Firat; Unal Erkorkmaz; Oguzhan Saylan

Aim: This experimental study was designed to produce ischemia-reperfusion injury in rat kidney by performing partial unilateral ureteral obstruction (PUUO) and investigated the effects of melatonin on the levels of oxidative injury parameters. Materials and Methods: Twenty-four adult male rats were randomly divided into three groups as follows; control group (Group 1); only nephrectomy and blood (5 ml) drawn from vena cava inferior, PUUO group (Group 2); PUUO (10 days)+ipsilateral nephrectomy after recovery of PUUO+blood from vena cava inferior VCI, melatonin treated group (Group 3); PUUO (10 days)+melatonin (1/2 hr before release, 50 mg/kg, ip)+ipsilateral nephrectomy after recovery of PUUO+blood from VCI. The left ureter was embedded into the psoas muscle to create PUUO. After 10 days, PUUO was recovered and ipsilateral nephrectomies were performed for biochemical analysis of superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA), glutathione peroxidase (GSH-Px), and protein carbonyl (PC) in the tissues and blood was drawn from inferior vena cava to study the same parameters in systemic circulation. The results were compared statistically. Results: The blood levels of MDA, NO, and PC were increased in the PUUO group in comparison to the sham-operated group (P<0.05). Melatonin treatment reduced MDA, NO, and PC levels in blood after PUUO recovery, but statistically significance consisted only for MDA and NO (P<0.05). The antioxidant enzyme activities (SOD, GSH-Px) were increased in the PUUO group (P<0.05). Melatonin treatment reduced SOD and GSH-Px activities in comparison with the sham-operated control group (P<0.05). Similarly, renal tissue levels of MDA, NO, and PC were increased in the PUUO group in comparison with the sham-operated group (P<0.05). Melatonin treatment ameliorated MDA, NO, and PC levels in renal tissue after PUUO recovery only MDA was statistically significant (P<0.05). Antioxidant enzyme activities (SOD, CAT, and GSH-Px) were increased in the PUUO group. Melatonin treatment caused reduction in SOD, CAT, and GSH-Px activities in comparison to the sham-operated control group (P<0.05). Conclusion: The results of this study showed that experimentally induced PUUO caused oxidative stress in rat kidney and melatonin treatment reduced oxidative stress and therefore may have a preventive effect on PUUO induced oxidative kidney damage in rats.

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Fikret Erdemir

Gaziosmanpaşa University

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Dogan Atilgan

Gaziosmanpaşa University

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Huseyin Ozyurt

Gaziosmanpaşa University

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Fatih Firat

Gaziosmanpaşa University

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